A = readmatrix ('NiI2_10VCOOL_spectra.csv')

x = A(:,1)
y1 = A(:,3)*1e12*0.6
y2 = A(:,5)*1e12*0.6
r = (y2-y1)./(abs(y2)+abs(y1))

hold on
%plot(x,y1,LineWidth=1,Color=[0.8 0 0])
%plot(x,y2,LineWidth=1,Color=[0 0 0.8])
plot(x,r,LineWidth=1,Color=[0 0 0])
xlim([500,700])
xticks(500:50:700)
ylim([-0.15,0.05])
yticks(-0.1:0.05:0.1)
set(gca,'XMinorTick','on','YMinorTick','on')
set(gca,'box','on','Xcolor',[0 0 0],'Ycolor',[0 0 0])
hold off
box on
set(gcf,'Position',[0, 0, 200, 200])